Flu cases appear to be peaking unusually early in the Pacific Northwest, where an increase in H1N1 cases is being seen in the community.

Dr. Helen Chu, a University of Washington professor of medicine and epidemiology, said flu in the region typically peaks in December or January, rather than early fall. She said the reason for the early surge is unclear. Falling vaccination rates may have left more people susceptible, or the circulating virus may have changed in a way that affects immunity.

Public health leaders are urging people to get vaccinated and ask their health provider about vaccine options. One option Chu described is FluMist, a nasal spray vaccine that can be ordered for administration at home.